Old Res Weather

Lexington, Massachusetts, USA

58°F

4/19/2024 5:12pm

Lexington Conditions: Clear
Temperature: 57.7°F / 14.3°C
Dew Point: 38.7°F
Relative Humidity: 49%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 30.06 in Falling Slowly
Visibility: 10 miles
Rain Today: 0.00 in
UV Index: $VPuv None

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 171909
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
309 PM EDT Wed Apr 17 2024

.SYNOPSIS...
Increasing cloud coverage this afternoon, rain chances increase
during the overnight hours mainly across western Massachusetts
and northern Connecticut. Cloudy, much cooler, with scattered
light rain continuing for Thursday. Dry and seasonable for much
of Friday with high pressure in control. A cold front brings 
another round of light rain showers Friday night into Saturday 
morning. Dry for the rest of Saturday with gusty winds. The dry 
stretch of weather continues into early next week with the next 
chance of wet weather Tuesday night and Wednesday as a frontal 
system approaches.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Highlights: 

* Showers likely for areas west of KORE, KORH, and KPVD. Outside of 
  a spot shower, much of eastern Massachusetts remains dry 
  overnight. 

Another great day across southern New England, but now the clouds 
are on the return ahead of a mid-level warm front. Showers and a few 
thunderstorms are extending in a line from Lake Ontario and points 
southeast to the New Jersey coast. This activity lifts northeast, 
arriving across southwest Connecticut and nearing the Hartford and 
Springfield metros this evening, post sunset. The eastern extent of 
the precipitation will be limited, as the mid-level warm front 
encounters drier air mass, the 12Z high-res models and CAMs do show 
this, with the eastern extent along a line from KORE, KORH, KPVD. 
While a spot shower east is possible, the area with the greatest 
likelihood of any appreciable rain will be areas west. Notably, the 
newer model run of the HRRR are looking less impressive in terms of 
areal coverage. Nevertheless, no adverse conditions are expected 
from these showers.  

Increased overnight cloud cover hold temperatures in the lower and 
middle 40s. Light winds become easterly heading towards day break.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Highlights: 

* An easterly wind will lead to a much cooler day, a few showers are 
  possible, though a washout is not expected. 

Mid-level ridge for Thursday, though a shortwave passage will bring 
our a few showers, not a washout by any means. At this point, kept 
POPs around 30 ~ Chance Rain. The more noticeable difference is the 
east wind, allowing for a raw/cool feel. High temperatures along the 
immediate coast are in the middle to upper 40s. Elsewhere, highs are 
lower and middle 502. Higher elevations in western Massachusetts are 
the coldest in the lower 40s.

East wind are 10 to 15 mph, with gusts along the coast to 25 mph. 

Precipitation chances come to an end overnight, though clouds and on 
shore flow does continue into the overnight hours. Do think spots 
along the eastern coast could see spot drizzle, but didn't have the 
confidence to include it in the WX GRID. Guidance this afternoon 
remained split on how much low level moisture would linger, so OPT 
to leave it out. Similar to the night before, our temperatures are 
in the upper 30s and low 40s. 

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Key Points...

* Mainly dry and seasonable Friday

* Scattered showers Fri night into early Sat followed by mild and 
  breezy conditions Sat afternoon

* Dry conditions return for Sun into Tue. Cooler Sun, then milder 
  Mon and Tue 

* Shower chances increase by Wed

Details...

Friday into Saturday...

Mid level shortwave departs by early Fri with weak shortwave ridging 
following. This will bring dry conditions for much of the day, 
although next shortwave and cold front will be approaching from 
western NY in the afternoon. We should see some sunshine develop, 
especially in eastern New Eng but trend will be for increasing cloud 
cover in the afternoon. Low risk a few showers could spill into 
western MA by days end but bulk of shower activity should hold off 
until Fri night. Near normal temps Fri.

Weak cold front moves into SNE Fri night with modest increase in 
moisture as PWATs increase to near 1" ahead of the front. This 
should bring a round of scattered showers Fri night which will 
likely linger into Sat morning, especially in the east as the front 
gets hung up near the coast. Then drying out in the afternoon with 
somewhat gusty W winds developing in the afternoon. Given the colder 
airmass will be lagging to the NW assocd with a secondary cold 
front, it should be a mild afternoon with temps reaching the 60s, 
and some upper 60s possible in SE MA. 

This secondary cold front is tied to a decent shortwave passage late 
Sat-Sat evening. The column is drying at this time but there may be 
a brief window for a few showers with the front late Sat in the 
interior. Did not include in the forecast at this time as confidence 
is low, but will re-evaluate in later forecasts.

Sunday through Wednesday...

Cooler post-frontal airmass settles in on Sunday with seasonable 
temps and abundant sunshine. Dry weather continues Mon and Tue with 
moderating temps. A potent shortwave is forecast to move off the mid 
Atlc coast Mon night-Tue but global ensemble guidance keeps moisture 
well to the south with a minimum in PWATs across SNE. Next northern 
stream shortwave approaches from the west Tue night and Wed. Timing 
and amplitude of the system is uncertain but risk for showers will 
increase by Wed. 

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Forecast Confidence Levels:

Low - less than 30 percent. 
Moderate - 30 to 60 percent. 
High- greater than 60 percent. 

Rest of today...High Confidence.

VFR. Increasing mid to high clouds across the interior this 
afternoon. Light south winds, except along the coast, on shore flow. 

Tonight and Thursday...High Confidence. 

MVFR ceilings and light showers develop tonight across western MA/CT 
with the best chance near and west of the CT River. These conditions 
will persist at times into Thursday. Meanwhile, across eastern MA/RI 
mainly VFR conditions are expected. Light southeast winds tonight 
becoming east between 5 and 10 knots on Thursday.

Thursday Night...High Confidence.

Lower end VFR and MVFR. Showers end, but areas of drizzle could 
develop along the coast. East wind 5 to 10 knots. 

KBOS TAF...High confidence. VFR for the TAF period. East wind the 
rest of today, becoming southeast overnight. While VFR on Thursday, 
CIGS are 050-070 along with a low chance of a spot shower. Left the 
mention out of the TAF do to the lower confidence. Wind becomes east 
once again Thursday around 10 knots. 

KBDL TAF...High confidence. VFR this evening, becoming MVFR around 
04z with -SHRA through 10z. Light southeast wind becoming 
east/southeast by daybreak. MVFR/low end VFR Thursday with spot 
showers possible and east/northeast wind around 10 knots. 

Outlook /Friday through Monday/... 

Friday: Mainly VFR, with local MVFR possible. Breezy. 

Friday Night: Mainly VFR, with local IFR possible. Breezy.
Chance SHRA.

Saturday: VFR. Breezy. Slight chance SHRA.

Saturday Night through Sunday Night: VFR. Breezy. 

Monday: VFR. 

&&

.MARINE...
Forecaster Confidence Levels:

Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent. 

Tonight through Thursday Night...High Confidence.

* Small Craft Advisory for Block Island Sounds and waters south
  of Block Island tonight and into Thursday. 

A weak wave of low pressure drops southeast across the mid- 
Atlantic with high pressure moving across the eastern Canadian 
Maritimes into Thursday. A few spot showers and perhaps a 
rumble of thunder possible. This will result in SE winds this 
evening shifting to the E by Thursday morning at speeds of 10 
to 15 knots. Some gusts up to 25 knots with marginal 5 foot seas
for the southwest waters, hence the newly issued Small Craft 
Advisory through much of Thursday. Seas may remain elevated 
enough to warrant the advisory to be extended into Thursday 
night for the waters south of Block Island. Future forecasts may
want to include this. 

Outlook /Friday through Monday/... 

Friday: Winds less than 25 kt. Seas locally approaching 5 ft. 

Friday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Chance of rain showers. 

Saturday: Winds less than 25 kt. Chance of rain showers. 

Saturday Night: Winds less than 25 kt. Seas locally approaching
5 ft. 

Sunday through Monday: Winds less than 25 kt. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 5 AM to 5 PM EDT Thursday for ANZ237.
     Small Craft Advisory from 5 AM to 8 PM EDT Thursday for ANZ256.

&&

$$

SYNOPSIS...KJC/Dooley
NEAR TERM...Dooley
SHORT TERM...Dooley
LONG TERM...KJC
AVIATION...KJC/Dooley
MARINE...KJC/Dooley